1. Field of the Invention
The present invention relates to a cutting distance calculating device for a multi-axis working machine.
2. Description of the Related Art
In general, as described in, for example, Japanese Patent Application Laid-Open No. 2008-221454, it is well-known that tool abrasion wear Tw is proportional to a cutting distance (a distance in which a tool moves for cutting) L, i.e., a relation of Expression (1) below holds between the tool abrasion wear Tw and the cutting distance L.Tw=K*L  (1)where, K is a proportionality factor, which changes according to an edge force of a tool edge tip due to a tool type/material, a work material, spindle speed, and feed speed, temperature, and the like.
When tool abrasion wear exceeds a tolerance, a tool exhausts the life thereof. Therefore, to learn the tool abrasion wear and the tool life, a cutting distance of a tool tip point position is important.
Japanese Patent Application Laid-Open No. 2008-221454 discloses a method of predicting tool abrasion wear from a prediction formula using an edge force (an edge force of a tool edge tip) and a cutting distance. The cutting distance is calculated from coordinate information (NC data) of an edge tip (a machining position) of an NC program. Specifically, in predicting tool abrasion wear before machining, a cutting distance is calculated by a simulation. In predicting tool abrasion wear during the machining, a cutting distance is calculated according to data obtained from a numerical controller that controls an NC machine tool.
Japanese Patent Application Laid-Open No. 2011-43874 (corresponding to US 2011/046773 A) discloses a technique for simultaneously acquiring actual position information of respective driving axes at respective times, calculating a three-dimensional coordinate value of a tool tip portion viewed from a coordinate system (a table coordinate system) fixed to a workpiece, and displaying a three-dimensional track of the tool tip portion using the three-dimensional coordinate value.